Moderate physical activity of up to two and a half hours a week does not increase the risk of knee osteoarthritis in adults aged 45 and older, according to a new study published in the Arthritis Care & Research journal.
“This study shows that engaging in physical activity at these levels is not going to put you at a greater risk of knee osteoarthritis,” said Joanna M. Jordan, MD, who is the senior study author and director of the Thurston Arthritis Research Center in the University of North Carolina School of Medicine.
“We found this held true no matter what a person’s race, sex or body weight is. There was absolutely no association between these factors and a person’s risk,” Jordan said.
Jordan and her colleagues analyzed the physical activity data of over 1,500 patients in UNC’s Johnston County Arthritis Project to test whether there was an association between the 150 minutes of physical activity per week and knee osteoarthritis.
The Johnston County Osteoarthritis Project is a population-based study of the hand, hip, spine and knee osteoarthritis and disability in Caucasians and African Americans 45 years of age and older.
The researchers found that patients who participated in 300 minutes of physical activity or more weekly had a higher, yet statistically insignificant risk of knee osteoarthritis compared to patients with 10 minutes or less physical activity per week. They found no correlation between the risk of knee osteoarthritis and patients participating in 150 minutes of physical activity.
“Moderate physical activities are those that produce some increase in heart rate or breathing, like rapid walking,” said Kamil Barbour, PhD, corresponding author of the study. “Meeting physical activity recommendations through these simple activities are a great way to reduce your risk of heart disease, stroke, high blood pressure, diabetes, and other diseases.”
The findings support Department of Health and Human Services (HHS) guidelines that recommend moderate weekly levels of physical activity, such as household chores, gardening, yard work, and walking.
Osteoarthritis of the knee is one of the five leading causes of disability among adults, according to the Centers for Disease Control and Prevention. About a third of adults over the age of 65 suffer from osteoarthritis, a progressive disorder of the joints caused by inflammation of the soft tissue, which worsens over time and leads to thinning of cartilage.